When the keyswitch is turned, it bridges the connection allowing power to the starter. If its bad, it wont let the starter do its job.
I FOUND THE SOLUTION!!!
Ok, I said sometime back that I'd get a pictorial showing how to repair the ' click ' problem our starters are notorious for. Well here we go...
If you have a 5 sided cover such as this one on your starter, the click problem is very cheaply repaired.
Remove the 3 small bolts or screws that hold this cover on. A plunger spring and gasket will all come off with the cover. Ignore the fact that I took this picture with the motor part off. DO NO remove and screws or bolts from the motor itself, but do remove the nut holding the motor's wire to the stud. You should see something similar to this..
Remove the larger nuts that hold the studs in, be careful not to break the wires that this terminal is attached to...
You can clean it a little bit, since I strip these to rebuild I clean with a glass bead blaster, comes out like this..
First part to put back in is the insulator on the starter side...
Then slide the contact in behind the terminal...(your contact may look different, but same principal)
Then slide the stud in ...
Slip the o-ring on..
Then the metal washer..
And the large nut. The battery stud comes out as a unit, normally pressed together...
As I said, contacts may differ a little in appearance, I replace with upgrades whenever possible...
Now with both contacts replaced we need to clean the plunger, a wire brush will do...
Put it back together, back on car, and look this thread up again 80,000 miles from now....